Highlights of the development in ultrasound during the last 70 years: A historical review.

This review looks at highlights of the development in ultrasound, ranging from interventional ultrasound and Doppler to the newest techniques like contrast-enhanced ultrasound and elastography, and gives reference to some of the valuable articles in Acta Radiologica. Ultrasound equipment is now available in any size and for any purpose, ranging from handheld devices to high-end devices, and the scientific societies include ultrasound professionals of all disciplines publishing guidelines and recommendations. Interventional ultrasound is expanding the field of use of ultrasound-guided interventions into nearly all specialties of medicine, from ultrasound guidance in minimally invasive robotic procedures to simple ultrasound-guided punctures performed by general practitioners. Each medical specialty is urged to define minimum requirements for equipment, education, training, and maintenance of skills, also for medical students. The clinical application of contrast-enhanced ultrasound and elastography is a topic often seen in current research settings.

Historia de la ecografía: Introducción en la Argentina: Pioneros en su utilización / History of ultrasound: Introduction in Argentina: pioneers in its use

Historia y desarrollo de la ecografía en Argentina, descripta a través de los distintos profesionales que fueron pioneros en su utilización.

A brief history of ultrasound in rheumatology: where are we going.

Musculoskeletal ultrasound is an evolving technique widely used in rheumatology thanks to the numerous advances and the improved work on standardisation. This article deals with the new developments in terms of technology and validation.

How ultrasound technologies have expanded and revolutionized research in reproduction in large animals.

Gray-scale ultrasonic imaging (UI) was introduced in 1980 and initially was used to examine clinically the reproductive tract of mares. By 1983 in mares and 1984 in heifers/cows, UI had become a tool for basic research. In each species, transrectal gray-scale UI has been used extensively to characterize follicle dynamics and investigate the gonadotropic control and hormonal role of the follicles. However, the use of transrectal UI has also disclosed and characterized many other aspects of reproduction in each species, including (1) endometrial echotexture as a biological indicator of circulating estradiol concentrations, (2) relative location of the genital tubercle for fetal gender diagnosis by Days 50 to 60, and (3) timing of follicle evacuation during ovulation. Discoveries in mares include (1) embryo mobility wherein the spherical conceptus (6-16 mm) travels to all parts of the uterus on Days 11 to 15, (2) how one embryo of a twin set eliminates the other without self-inflicted damage, and (3) serration of the granulosum of the preovulatory follicle opposite to the future rupture site as an indicator of imminent ovulation. Studies with color-Doppler UI have shown that vascular perfusion of the endometrium follows the equine embryo back and forth between uterine horns and follows the expansion of the bovine allantochorion throughout each horn. In heifers, blood flow in the CL increases during the ascending portion of an individual pulse of PGF2α metabolite and then decreases. These examples highlight the power of UI in reproduction research. Without UI, it is likely that these and many other findings would still be unknown.

Noninvasive vascular testing--a 35-year reflection.

Noninvasive vascular testing has made a major contribution to the care of vascular surgery patients. This article a reflection on a 35-year corroborative association with Doctor Norman Rich, during which many of the advances in noninvasive vascular testing have been witnessed and effected. I served my vascular surgery fellowship under Doctor Rich in 1967-68 at Walter Reed Army Hospital. The only noninvasive vascular equipment then was a pencil probe Doppler. The value of the Doppler in the management of peripheral vascular disease that year and in determining limb viability in combat surgery in Vietnam the following year was established, and both experiences were published. Later, Doctor Rich established the annual Military Vascular Surgery Meeting and was appointed as the first Chair of the Department of Surgery at the Uniformed Services University for Health Sciences (USU). I entered private practice in Central California in 1976, and ultrasonic imaging was developed which allowed noninvasive examination of the carotid arteries. I then developed a protocol to screen for the three silent, immediate causes of stroke, employing a "a quick carotid scan" for carotid artery disease, a lead II rhythm strip for atrial fibrillation, and blood pressure determination for hypertension so that these common causes of strokes could be recognized and treated, and potentially prevent the majority of strokes. My association with USU, Doctor Rich, and others involved proved instrumental in initiating implementation of stroke prevention screening. The structure established at USU provides a means of establishing the protocol nationally. Noninvasive vascular testing is an addition to Medical Science that has led to significant improvements in individual patient care and that has the potential of allowing a major reduction in death and disability from stroke and other vascular diseases. Throughout a 35-year collaborative association with Doctor Norman M. Rich, I have witnessed and developed many of these advances. These contributions to noninvasive vascular testing reflect the value of our collaboration.

Christian Andreas Doppler--the man and his legacy.

AIMS: Reminding the life and legacy of the Austrian Scientist who discovered the famous 'Doppler Effect'. METHODS AND RESULTS: C.A. Doppler was born the 29th of November 1803 in Salzburg. After studies in Linz and Vienna, he graduated in mathematics, became assistant at the University and later worked as a professor in Prague. Back to Vienna, he was appointed as professor at the Polytechnic School and --in 1850--as first director of the new Institute of Physics. C.A. Doppler did publish on magnetism, electricity, optics, and astronomy. He remains in the history of science due to the discovery presented (May 25, 1842) at the Royal Bohemian Society of Science entitled "On the colored light of the double stars and certain other stars of the heavens"; the paper described (applied to light) the shift of frequency which bears nowadays his name. The theory was later experimentally proven and--extended for any electromagnetic and acoustic waves--got myriads if applications in astronomy, physics, aviation, meteorology, and health science. Satomura in Japan (1955) published it's first ultrasound vascular application--with successive achievements in the next decades. CONCLUSION: Doppler ultrasonagraphy became the main noninvasive instrument for functional assesment of heart and vessels.

Christian Doppler is 200 years young.

Christian Doppler was born 200 years ago in Salzburg, Austria, on November 29, 1803, worked in Prague and Vienna and died 150 years ago in Venice. In an article of eight pages he described the principle, which made him famous. It appeared in 1842 with the exotic title: "On the Coloured Light of the Double Stars and Certain Other Stars of the Heaven". The validity of his principle for velocity measurement was confirmed by trumpet sounds produced on a train moving towards and away from the observer. Around 1960 Japanese scientists suggested that flow velocity in blood vessels could be determined by analysing the difference of frequency between emitted and backscattered ultrasound. Rushmer and coworkers built machines suitable for medicine in Seattle, where Eugene Strandness recognized their potential and applied them in first studies. In 1967 the technique jumped to Europe and started to be used worldwide. Already by using continuous wave ultrasound it was possible to diagnose occlusive disease of neck and limb arteries, venous thrombosis and valvular insufficiency with accuracy. Measurements of postestenotic ankle blood pressure were facilitated by Doppler sensing. Over the years more sophisticated instruments were developed. Pulsed emission of ultrasound waves opened a way to study flow velocity profiles across large vessels. By combining the method with A or B mode ultrasound blood flow could be quantified and finally perfused segments of blood vessels visualized. Duplex scanning in its simple and then in its colour coded version is nowadays the standard non-invasive technique that nobody would like to miss. Vascular territories like intracranial, renal and intestinal arteries can also be explored. For the assessment of microvascular flow in skin and mucosae laser Doppler instruments were introduced.

Those who faced turbulence and launched the era of flow dynamic concepts for cardiac investigation.

This paper puts emphasis on pioneers who developed cardiac flow dynamics concepts during the second half of the 20th century at a period where pressure measurements were the rule. Thinking flow instead of pressure dynamics corresponded to in-depth conceptual changes: whereas blood pressure generally has a single positive sign and a similar pattern at all points of a cardiac chamber or a vessel, flow fluctuates around the zero line and its pattern changes within a given cardiac chamber or vessel level. These specific changes and fluctuations were the exciting tools needed to renew our pathophysiological insights, just in time with the take off of Doppler ultrasound making noninvasive investigation of fluid dynamics easily available. Each decade was marked by a specific historical contribution to evolving concepts. Instead of a merely phenomenological approach to flow dynamics, pioneers assigned a value of paradigms to basic flow patterns. They generated a system of heuristical hypotheses which turned out to underlay a modernistic understanding of flow dynamics in normal and diseased hearts. So far, flow investigation had definitely gained acceptance completing pressure data at the middle of the 1980s, widely opening a breakthrough for future pathophysiological insights.

Elastography--the movement begins.

The advent of real-time ultrasound in the 1970s, together with a growing interest in tissue characterization, led to a number of investigators using the nature of tissue motion to distinguish healthy from diseased tissue. Our group at the (then) Ultrasonics Institute demonstrated the use of phase methods for detecting very small tissue motions, using natural stimuli. The method could also be applied in the lag (autocorrelation) domain to directly measure the amount of deformation to high accuracy. This method was also applied to measuring the amount of dilatation of blood vessels using both conventional and intravascular ultrasound. A basic limitation of these techniques was the poor spatial resolution, and quasistatic methods soon replaced this method of measuring tissue deformation. However, a new way of assessing the health of tissues had been established.

Cardiovascular applications of the Doppler technique: A long way from birth to scientific acceptance.

Analysis of the early developments of cardiac Doppler illustrates a gap, frequently encountered in science, between initial concepts and final acceptance. Acceptance may only emerge as a result of multidisciplinary collaboration and fruitful dialogue between physicians, physiologists, physicists, and engineers. By 1980, after a good deal of trial and error and a long period of incremental improvement, the majority of the theoretic and scientific issues had been defined. The explosive development of Doppler techniques can now intervene to sweep aside the medical community's scepticism.

The history of ultrasound.

Diagnostic medical ultrasound may have a brief history, but its roots date back to the early nineteenth century. From its modest beginnings in military institutions where ultrasound was used to examine pathologic specimens, to the routine evaluation of the fetus, injured patients, and those with cerebrovascular disease, ultrasound has secured a position as a key diagnostic test both currently and in the future. Its ability to diagnose valvular and congenital heart disease has reduced the need for invasive cardiac angiography with its attendant risks. Furthermore, endoluminal, transvaginal, transrectal, and transesophageal ultrasound have expanded physicians' diagnostic armamentarium and ability to "look inside" their patients. Notwithstanding all these advancements, ultrasound research and development continue to be fostered, and the ideas of today will be the technology of tomorrow (Fig. 5).

A brief history of Doppler ultrasound in the diagnosis of peripheral vascular disease.

The history of Doppler ultrasound in peripheral vascular diagnosis is considered in terms of basic developments, clinical applications and impact on medical practice. Many early developments occurred at Osaka University in Japan and the University of Washington in the United States. Through progressive steps, Doppler ultrasound technology has provided clinical applications in blood-flow sensing, waveform analysis, localizing blood flow and two-dimensional (2-D) mapping of blood flow. An important advance was the development of duplex and color Doppler scanning. Real time velocity measurements and flow mapping have led to many clinical applications. Two important applications have been detection and grading of atherosclerotic plaques in the internal carotid artery and the diagnosis of deep venous thrombosis. Doppler ultrasound is the preferred noninvasive imaging method for each of these clinical problems. The recent reaffirmation of carotid endarterectomy as the appropriate management for certain categories of carotid atherosclerotic occlusive disease has led to guidelines for selecting patients for carotid endarterectomy. New Doppler ultrasound criteria are being developed to identify categories of stenosis that relate to these guidelines. The establishment of Doppler ultrasound has led to training programs for technologists and physicians, certification of technologists and establishment of standards and quality control measures for vascular laboratories.